Screen idols: higher resolution means better laptops

Extreme Hardware Intel’s latest Ivy Bridge chipset, currently being deployed by every laptop manufacturer on new machines, is capable of supporting resolutions of up to 4096 pixels horizontally, using integrated graphics.

Known as 4K, these ultra-high resolutions are gaining support in professional video cameras. So why do Samsung, Sony, Lenovo and the rest slap a relatively low-resolution, 15.6in, 1366 x 768 screen on a laptop that is maxed out in every other area?

Apple’s iPad, which has a 9.7in screen, has a resolution of 2048 x 1536 pixels. That is a pixel density of 246ppi.

Unique: Apple's 2880 x 1800 'retina display' MacBook Pro

The iPhone 4 and 4S have an even higher pixel density: 326ppi. And Apple is not the only tablet and smartphone manufacturer offering high-density screens. Asus has a tablet in the works with a 1920 x 1080 display, and there are lots of smartphones on the market with pixel densities well above 200ppi.

Squeezed middle

Yet laptop manufacturers stick with screens that can only be described as "HD" because they just manage to squeeze in more than 720 vertical pixels – the fewest required to meet the HD spec.

There are several reasons for this. One is that adding a higher-resolution screen to a laptop adds to the cost of production. When manufacturers are operating on wafer-thin margins and trying to outdo each other on price, there has to be a very good reason for increasing cost – and bumping up the screen resolution just doesn’t offer enough wow factor to take that risk.

The second reason is battery life. More pixels means more light, which means more power, and that sucks battery life. It is a trade-off that manufacturers don’t think we users are willing to make.

Laptop makers stick with screens that can only be called "HD" because they just squeeze in more than 720 vertical pixels

Resolution is not the only issue, of course. Laptop screens are notoriously poor at displaying consistent colour across a wide viewing angle.

And then there is the thorny issue of how many colours the screen can actually display. Most companies will tell you that their screens display "millions of colours". What they won’t explain is that the vast bulk of those colours are fudged.

Twisted logic

That is because most laptops still use Twisted Nematic (TN) displays, which are notorious for poor viewing angles, low contrast and an inability to display 24-bit colour.

Natively, TN panels use six bits to record the intensity of each of the three primary colours shown by a given pixel and use a form of interpolation – as the fudging is known technically – to display the other several million colours visible to the human eye.

Tablets outdo notebooks

If that was the only technology available to laptop manufacturers they might be forgiven, but tablets, including Apple’s iPad and several Android slates, have IPS (in-plane switching) panels.

High-end LCD monitors also have IPS displays. These panels have a wider viewing angle than TN displays and more accurate colour reproduction, and can display 24-bit colour natively.

Try and find a mainstream laptop with an IPS panel, however, and you will be sorely disappointed. They tend to be reserved for mobile workstation notebooks with 15.6in and 17in screens rather than the much more common laptops with 15in screens or smaller. Why? Cost, mainly.

Try and find a mass-market laptop with an IPS panel and you will be sorely disappointed

IPS panels have a lower yield on the production line than their TN counterparts and so are more expensive to produce. Dell believes that the benefits of including them in smaller laptops don’t justify the additional expense.

So Dell reserves IPS panels for users working in photography or graphic design or content creators who demand superior colour accuracy.

No peeping

Asus too takes the view that TN panels are good enough for most users and that moving to IPS is still too costly. Laughably, it has also claimed that wider viewing angles expose your work to prying eyes: peeking peepers don't need to stand so close.

Despite Asus’s low regard for IPS panels, two of its most recent small-screen laptops do sport them. The Zenbook UX21A and UX31A both have IPS panels and will be available with resolutions up to 1920 x 1080 pixels. Where can you buy one? Er… you can’t, but they are on their way.

Sony's Vaio SE has one of the few Full HD IPS laptop LCDs

Sony’s Vaio SE, however, is available now, costs less than a grand and has a 15.5in, 1920 x 1080 IPS panel. That is hardly the mainstream, but it looks like hopes of seeing an IPS panel in a sub-£500 laptop are unlikely to be realised in the near future.

There is better news on the way, however. Samsung is busy developing active-matrix organic light-emitting diodes (Amoled) screens for laptops. These screens, widely used in smartphones by Samsung, HTC and Nokia, have much higher contrast than TN displays and wider viewing angles.

As with IPS, however, production yields on the panel sizes needed for laptops are not great so costs are high.

That is likely to mean that, initially at least and probably until 2014 at the earliest, Amoled and its HD and touch-screen variants will be reserved for high-end laptops, as well as for smartphones and tablets. ®